The invention relates to a locking device for a vehicle seat.
Such a locking device comprises a blocking element which has a supporting surface, and a locking element which is movable with respect to the blocking element, said locking element having an end face and facing the supporting surface of the blocking element with the end face in a locked position of the locking device, such that the locking element and the blocking element are not movable past one another and the assemblies of the vehicle seat are thus blocked with respect to one another. By moving the locking element, the locking device can be unlocked, and so the assemblies of the vehicle seat can be moved with respect to one another.
The assemblies of the vehicle seat may be for example a seat part that provides a sitting surface for a vehicle occupant, and a backrest part that is pivotable with respect to the seat part. Via the locking device, the backrest part and the seat part are kept in position with respect to one another, wherein, by unlocking the locking device, the backrest part can for example be folded forward in order to create access to a vehicle space located behind the vehicle seat or to move the vehicle seat into a flat position in order to enlarge a loading space of the vehicle or to create a storage space.
In the locking device, locking takes place in that surfaces of the blocking element and of the locking element oppose one another. In the case of a locking device known from DE 10 2014 216 951 B3, the locking element is realized for example by a friction finger which interacts with a blocking element in the form of a pawl in order to keep the blocking element in position in a locked position of the locking device, such that the blocking element cannot be lifted out of an associated toothing. The friction finger is in frictional contact with the blocking element in the form of the pawl in the locked position, wherein, by moving the friction finger, the blocking element can be adjusted and as a result unlocked.
In the case of a locking device known from DE 44 39 644 C2, a locking element referred to as a securing member is in frictional contact with a blocking element in the form of a pawl, when the locking device is locked. The locking element has a non-self-locking clamping face which secures the pawl in a blocking position, and a catching surface which braces the locking element against the pawl in the event of a crash and thus keeps it in position.
A further locking device is known from EP 2 288 512 A1.
In the case of a locking device of the type described here, a general conflict is that the locking device is intended to lock the assemblies assigned thereto securely and reliably in the locked position even in the event of great loads, and must not open unintentionally for example in the event of a crash, but nevertheless is intended to make unlocking possible easily without great effort. If a locking device is designed for a particularly reliable hold under great loads, in particular in the event of a crash, this can result in a lack of smoothness in operation. If, conversely, the locking device is designed for easy, comfortable actuation, this can impair the hold in the event of a crash. This conflict is amplified even further in that tolerances are unavoidable on locking devices, and moreover a coating layer or grease layer may be present on the mutually facing surfaces of the blocking element, for the one part, and of the locking element, for the other part, said layer influencing the frictional interaction between the elements, and surface changes can occur during operation on account of continuous loading of a vehicle seat. Therefore, a situation in which a lock may open under particular loads or parts seize up and the locking device can no longer be easily actuated cannot be ruled out.
Therefore, there is a need for a locking device for a vehicle seat, which ensures reliable locking, is easy to actuate and is additionally insusceptible to wear.